Method of producing light-colored sirups



Patented Apr. 11, 1950 METHOD OF PRODUCING LIGHT-COLORED SIRUPS Leo M.Christensen, Lincoln, Nebn, assignor to National Agrol Company,Washington, D. C., a

corporation of Michigan No Drawing. Application May 24, 1946,

Serial No. 672,169

11 Claims. 1

This invention relates to a method of producing light-colored syrupsfrom starchy material, more particularly to a novel method of producingsyrups of a highly desirable light color from starchy material byenzymatic conversion.

As is known, at the present time, there are two general methods employedfor the manufacture not. The original hydrolysate generally containsonly about of sugars and in commercial practice it must be evaporated toa concentration of about 60 to about 65% sugars. This concentration maybe effected at atmospheric pressures or at lower temperatures underreduced presof sugar or sugar syrups from starch or starchcontainingmaterials. The process most generally employed comprises the separationof the starch from the other grain constituents, by suitable mechanicalmeans, and its subsequent conversion,

by cooking with dilute mineral acids, to a mixture of sugars includingdextrose and maltose. The second process involves the use ofsaccharifying enzymes such as the amylases of malt, mold bran andcertain bacteria. These amylases serve to convert the cooked starch tosugars. The products produced from the described process are generallydesignated acid converted or enzyme converted syrups respectively.Dextrose and maltose may be recovered from these syrups in crystallineform by methods well-known in the art.

Enzyme converted syrups possess a distinct inherent advantage ascompared to acid converted syrups. Such enzyme converted syrups containabout the same amount of dextrose, about twice the amount of maltose andonly about half of sures; in either case'the color begins to developwhen the sugar concentration reaches about,40%, by weight, and the colorintensifies as the concentration progresses. In the past, efforts havebeen made to reduce this undesired color of the enzyme converted syrups.Treatment of the original hydrolysate with a good quality ofdecolorizing carbon reduces the color somewhat, and the concentrated orpartially concentrated syrup may be somewhat decolorized by suchmethods. However, these methods are expensive and are performed withdifliculty when applied to the viscous syrups.

As a result of intensive experimentation in this field it has beenfoundthat the color and much of-the flavor of the enzyme convertedsyrups does not derive from proteins, as had previously been supposed,but from other constituents of the grain. Thus, when pure starch, suchas is made by a very careful mechanical separation from other grainconstituents is employed, the color and flavor, generally speaking, arejust as pronounced as though large amounts of protein had the amount ofdextrins as are produced by acid been originally present. It has beenascertained conversion. Since the dextrins have no sweetas a result ofintensive investigation that the imening power, the enzyme syrups arethus sweeter purity in the starting material which ultimately than theacid converted syrups. However, this gives rise to the color in thesyrup, and to some advantage, while recognized in the past, has beenextent, the flavor, was derived from some conoffset considerably byreason of the fact that the stituent of mechanically purified starch,and not, enzyme converted syrups are brown in color and strictlyconsidered, a protein. have certain flavors that makes their use objec-It has long been known that starches contain ,tionable in many products.For these reasons the in their cell walls certain sterols, waxes andphosenzyme converted syrups have found but a lim-- pholipids. Theseproducts are water insoluble ited commercial use even though, as noted,they 40 and are not solubilized by acid conversion. Howare superior insweetening power. ever, it has been determined that the common It hascommonly been assumed or postulated amylase preparations hydrolyze theseconstituthat the color and much of the flavor of the enents to watersoluble forms, furthermore, it has zyme converted syrups are due to sometype of been ascertained that these compounds readily chemicalcombination of sugar and proteins. lose water on heating and thedehydrated deriva- These proteins are present because of the fact tivesthus produced are highly colored. that the enzymatic saccharifyingagents used It was then found that if these color-forming containproteases as well as amylases, and thus bodies could be removed from thestarting mabring into, solution larger amounts of amino acids terial theundesired color of enzyme converted and polypeptides than are derivedwhen acid consyrups could be substantially eliminated. To esversion isused. This is particularly true when tablish this fact a quantity ofpurev corn starch the enzyme conversion is applied to ground whole wasextracted with a solvent for the sterols, grain as is not infrequentlydone. waxes and phospholipids and the extracted This color, typical ofenzyme converted syrups, starch was subsequently converted to syrup. Fordevelops during the concentration of the prodthis purpose grams of purestarch was ex- 3 tracted with petroleum ether. By reason of thisextraction 0.25 gram of an oily impurity was recovered. The extractedstarch was then converted by enzymatic conversion and was found to havethe composition generally obtained by other methods of saccharificationand was practically water whitein color. Further experimentationdemonstrated that to obtain such water white enzyme converted syrups itwas not necessary to use starch but that ground whole grain could beemployed and that if such grain is extracted with a good fat solvent italso could be converted by enzymatic agents to yield a syrup of very lowcolor without decolorizing or bleaching. Obviously, any readilyavailable eilective fat solvent may be employed such, for example, aschlorinated hydrocarbons and the like.

It will thus be seen that the broad concept of the invention comprehendsthe defatting of the starchy material at any suitable stage before thedevelopment of color. For obvious reasons this defatting is carried outon the dry raw material but in view of the availability of effectivewater immiscible fat solvents it is apparent that defatting may becarried out at any desirable stage in the process. As will be seenhereinafter the defatting of the starchy material presents otheradvantages of prime economic importance in respect to the filtration ofthe saccharified mash.

In carrying out the invention it is preferred to start with whole groundgrain or with starch rich in grain fractions although it will beappreciated that any starchy substrate may be employed. The dry startingmaterial is extracted, as previously noted, with an effective waterimmiscible fat solvent, such as petroleum ether, trichlorethylene andthe like, and such extraction is continued until substantially 95% ofthe fat content is extracted. Such extraction may require from aboutone-half hour to as long as 8 hours more or less, depending upon thephysical character of the material, the solvent and the type ofequipment used. Preferably the grain is ground to mesh or finer and istreated in an efiicient extraction unit. With effective separatingconditions the fat-like constituents are substantially completelyremoved within a period of about an hour. The solvent, as will beappreciated, is passed through an evaporation and recovery system andthe denuded solvent is recycited to the extractor. The recovered fatsmay be utilized for any desired purpose.

The defatted starchy fraction is then mixed with from 2 to 3 parts ofwater and cooked. If the starchy material is substantially pure starchabout 3 parts of water are employed such amount being less if thestarting material contains less starch. In the preferred operation thestarchy material is first moistened with about one-half the amount ofwater and this slurry is introduced into the balance of the water, thelatter being at a temperature high enough to insure substantiallyinstantaneous gelation. When corn is the starting material employed thistemperature should be above 65 C.

The aqueous starch slurry is then cooked for suitable period of time as,for example, for a period of about 5 minutesat 150 C. or, if desired,for a longer time and at a commensurately lower temperature.

As is known and as scribed in U. S. Patent curred in cooling cooked mashdown to the saccharification temperature when normal methods of slowcooling are employed. These losses ap- 2,342,330, losses are inpear tobe due to I from which the data of Table is more particularly deeconomicsignificance an irreversible hydration of the starch during the orthodoxstep of slow cooling of cooked starch from a temperature of about C.down to the optimum saccharification temperatures, which latter areabout 60 C. for malt and about 55 C. for mold bran. In the presentprocess therefore this quick cooling with consequent avoidance of starchretrogradation is recommended to thereby insure higher sugar yields.

The cooked starch may be preliminarily cooled by evaporation at reducedpressure after which it is added with instantaneous mixing to a volumeof cold water containing approximately 10 pounds of malt orapproximately 3 pounds of mold bran, or their equivalent in amylasecontent, per 100 pounds of the original grain. .The volume andtemperature or the cold water is ad- Justed so as to practicallyinstantaneously reduce the temperature of the mixture to the optimumsaccharification temperature which in the case 0; mold bran, as notedabove, is substantially 5 C.

This saccharifying mash is then maintained at a temperature of from 45C. to 55 C. for a period move larger fiber particles and is thereafterfiltered to remove suspended matter. The filtrate may be treated withdecolorizing carbon if the malt or mold bran have yielded anyappreciable color to the solution. Such colors, if present, are thecarbon. Thereafter the clarified filtrate is evaporated, preferabl atreduced pressures, to a syrup of the desired concentration. Thereactionthroughout the process should be pH 4.8 to pH 5.5.

As noted previously, the preliminary step of defatting the grain, orother starchy substrate, results not only in the production oflight-colored syrup but also insures marked economies in the filtrationstep. As is known, the filtration of the saccharified mash, prior toevaporation, is the most diificult operation in the whole enzymaticsyrup process. It has been ascertained that when defatted starchymaterial is employed not only is the amount of suspended matter to beresuch preliminary defatting is not carried out.

These major benefits are apparent from the data in the following table.In the operation I is derived, the saccharified mash was first screened,then centrifuged, in a solid bowl centrifuge, and filtered on a suctionfilter through paper.

Table I Deiatlcd corn meal Corn meal Suspended matter in centritugate,Filtration rate of centrifugate, Ga

sq. it., without filter aid Filtration rate of centriiugate,Gallons/minute/ sq. in, with filter aid From an inspection of the datain the table it -will be observed that by removing the fat contentequally with and without a filter aid. This rapid filtration, as will beappreciated, is of profound since for the same thruput the filtrationarea required for processing deiatted corn is but one-fifth of thatnecessary for the undefatted corn. Furthermore, it has been found thatwhen defatting is invoked the filters can be operated substantiallytwice as long between cleanings as when undefatted grain is used.

It will be appreciated that utilization of the principles of the presentinvention insures not only marked economies in the production of enzymeconverted syrup but also results in a novel product, i. e., a syruphaving the desired sweetening power of the enzyme converted syrupscoupled with the low color value characteristic of the acid convertedsyrups.

While a preferred method of efiectuating the principles of the inventionhave been described it will be understood that this is givendidactically as one illustrative method of achieving the advantages ofthe novel basic concept, namely, 01 the discovery of the essential colorimparting factor in the source material and its removal at any suitablestage in the operation by any appropriate procedure.

I claim:

1. A method of producing syrups of high sweetening power and low colorwhich comprises, ex-

tracting a starchy substrate with a solvent for sterols and waxes untila substantial proportion of the sterols and waxes are removed, heatingan aqueous slurry of the extracted starch to effect gelation thereof,cooking the starch at elevated temperatures, then cooling the cookedmash to optimum saccharification temperatures and inoculating the cooledmash with an amylase-containing saccharifying material.

2. A method in accordance with claim 1 in which the amylase-containingmaterial is a vegetable amylase.

3. A method in accordance with claim 1 in which the amylase-containingmaterial is a iungal amylase.

4. A method in accordance with claim 1 in which the amylase-containingmaterial is barley malt.

5. A method in accordance with claim 1 in which the amylase-containingmaterial is mold ,bran.

6. A method in accordance with claim 1 in which the amylase-containingmaterial is a mixture of barley malt and mold bran.

'1. A method of producing syrups of. high sweetening power and low colorwhich comprises, extracting a starchy substrate with a water immisciblefat solvent, heating an aqueous suspension of the extracted starchymaterial to effect gelation of the material, cooking the material atcooking temperatures, rapidly cooling the cooked mash to optimumsaccharification temperatures and without substantial retrogradation ofstarch and saccharifying the cooked mash with enzymatic saccharifyin'gmaterial.

' .8. A method of producing syrups of high sweetening power and lowcolor which comprises, extracting a starchy substrate with a waterimmiscible fat solvent, heating an aqueous suspension of the extractedstarchy material to effect gelation thereof, cooking the material atsuitable cooking temperatures, rapidly cooling the cooked mash tooptimum saccharification temperature by quickly mixing the cooked starchwith the requisite amount of cold water containing an enzymaticsaccharifying agent, maintaining the saccharifying mash at such optimumtemperature for a period of time sufilcient to insure the desiredsaccharification, screening the saccharified mash, filtering outsuspended matter and evaporating the filtrate to the desired sugarconcentration.

9. A method according to claim 8 in which the converting agent is barleymalt.

10. A method according to claim 8 in which the converting agent is moldbran.

11. A method according to claim 8 in which the converting agent is amixture of barley malt and mold bran.

LEO M. CHRISTENSEN.

REFERENCES CITED The following references are of recordin the file ofthis patent:

UNITED STATES PATENTS 7 Date

1. A METHOD OF PRODUCING SYRUPS OF HIGH SWEETENIGN POWER AND LOW COLORWHICH COMPRISES, EXTRACTING A STARCHY SUBSTRATE WITH A SOLVENT FORSTEROLS AND WAXES UNTIL A SUBSTANTIAL PROPORTION OF THE STEROLS ANDWAXES ARE REMOVED, HEATING AN AQUEOUS SLURRY OF THE EXTRACTED STARCH TOEFFECT GELATION THEREOF, COOKING THE STARCH AT ELEVATED TEMPERATURES,THEN COOLING THE COOKED MASH TO OPTIMUM SACCHARIFICATION TEMPERATURESAND INOCULATING THE COOLED MASH WITH AN AMYLASE-CONTAINING SACCHARIFYINGMATERIAL.